[vorbis-dev] window function

hkato hkato at beige.ocn.ne.jp
Wed Jul 23 06:02:07 PDT 2003



Dear Sebastian and all,

This is a Japanese to live in Japan.
I have a question. 
Ogg's window functon is

f(x)=sin(1/2*pi*sin^2((x+0.5)/n*pi)) for 0 <= x < n

But I cannot understand why this window function satisfys
the equation

f^2(x)+f^2(x+n/2)=2

which is for MDCT's perfect signal reconstruction.

reference:
Analysis/Synthesis Filter Bank Design Based on Time Domain Aliasing Cancellation
John P. Princen, Alan Bernard Bradley
IEEE Transactions on Acoustics,Speech and Signal Processing  vol.ASSP-34,No.5,October 1986 

<p>If you know the reason why,please teach me.

Regards,

Kato

-------------------------------------------------------------------------------------------
>Vorbis Development List, November 2002
>[[vorbis-dev] MDCT-Window still wrong]
>From: Sebastian Gesemann (sgeseman at uni-paderborn.de)
>Date: Wed 13 Nov 2002 - 14:56:39 EST
>
>In vorbis-spec-intro.html, the MDCT-Window is still wrong.
>
>Should be sin(1/2*pi*sin^2((x+0.5)/n*pi))
>for 0 <= x < n
>
>bye,
>Sebastian 

<p>--- >8 ----
List archives:  http://www.xiph.org/archives/
Ogg project homepage: http://www.xiph.org/ogg/
To unsubscribe from this list, send a message to 'vorbis-dev-request at xiph.org'
containing only the word 'unsubscribe' in the body.  No subject is needed.
Unsubscribe messages sent to the list will be ignored/filtered.



More information about the Vorbis-dev mailing list